Monday, August 28, 2006

Even I may be guilty of overdoing it, but maybe it's the ghosts of storms past that looked innocuous and ended up being torrential rainmakers that caught many by surprise. Those of us in the Carolinas to the Mid-Atlantic will welcome the rains that are to come, but it will make for a very wet end to the summer travel season this Labor Day Weekend. Click on the graphic below for the most up-to-date forecast map from NHC.

The section I wrote below was issued via the email distribution list this afternoon. Granted my ideas on windspeed intensity may not pan out as I think it is doubtful this storm will ever regain hurricane status again. But in the same breath I think back to Ivan in 2004, and how the models were trying to tell us something about the eventual track, but no one could figure it out until we noticed the circulation center had actually maintained it's structure, crossed back over Florida, reemerged in the Gulf and almost made it back to hurricane strength believe it or not before hitting Texas as a medium-range tropical storm. I wonder if the East Coast stall scenario playing out on the maps is an indication that this will turn into a massive rainmaker.

Written at 3:30 PM 8/28

UPDATED ANALYSIS OF ERNESTO’S FUTURE TRACK, LANDFALL AND INTENSITY

Ever-changing Ernesto has been confounding forecasters, including me, since the first 5 day projection was issued. It’s a good thing we all have instant access to technology and have been able to monitor the movement of this storm. It seems that each time a forecast was issued, the storm was already in the process of undoing that forecast. Obviously my predictions issued on Saturday have proven to be way off, but at least it is a relief to storm weary residents of the Gulf that what I projected did not come true.

My main concern for the future of this storm is the computer models continue to have a difficult time initializing the storm, mainly because the center of circulation keeps reforming in different places. Since the major models commence a data run every 6 hours, the storm has changed so much that by the time an updated forecast track is ready to be issued, the information already seems inaccurate. This is not a knock on forecasters, mind you, it is just one of the many reminders that even the most powerful computers in the world may never be able to uncover the nuances and inner complexities of tropical systems.

That leads me to the big issue…which is almost like a repeat of the winter storm rule: “Predict the High and you predict the storm.” I can’t take credit for the rule, it was created by a Penn State meteorology professor, but I have applied it to my storm analysis and sometimes it works out. That’s where I’m going to hang my hat with Ernesto. Here’s a scenario I see happening based on the uncertainty we’ve experienced thus far..based on a trend first picked up by the European models which is shown below (valid for 7AM Saturday)

Several models show a large Canadian high moving off the New England coast by end of the week..but not so much that the high provides an easy escape for Ernesto as with Floyd in 99. The problem is that this could become a defacto “blocking high” because it may not move off fast enough. The storm appears to be heading out to sea or at least raking the coast with tropical storm to hurricane force winds for days on end. When it begins to turn northeast, it appears the Mid-Atlantic is spared (when in actuality a nice soaking rain would be just right about now). Instead of racing off to the northeast, the storm slows and gathering strength over the Gulf stream near the Carolinas. Then, as the high slowly fades east, a trough develops along the Mid-Atlantic, the pressure gradient tightens as the storm approaches, and placement of the high sends a large, slowly eroding hurricane back over the NC-MD I-95 corridor similar to Isabels’s path, only just a bit farther north. Hurricane watches and warnings are quickly raised, but the public is given less than 24 hours notice due to the rapid change in the forecast. The end result is a slow-moving, 75 mph hurricane moving along the DelMarVa or even in the southern bay..stuck between two highs..one in the North Atlantic and the other in southeast Canada. (10 PM update: doubtful we'll see winds of that strength now, but we could see the equivalent in rain..5-10")

Post below was written at 5:30 AM 8/28

WILL THIS STORM EVER MAKE UP IT'S MIND

or maybe the headline should read

HMMM, INSURANCE COMPANIES WILL

BE THRILLED ABOUT THIS FORECAST

Now you're saying, "Come on Foot, as if the storm has any control over where it's going." Well, I'd like to counter by saying that although everyone, including me, has been waaay off on the path of this indecisive storm, there is some truth to the idea the storm can determine where it goes next.

Last night I wrote these notes and did not get a chance to post them, but I believe this is still valid considering how much the forecast has changed. While Tampa-St. Pete will be spared a $50 billion direct hit, Miami and the Southeast Coast will get menaced instead for very unpleasant unofficial end to summer.

Here's my thoughts on what is happening with the track changes:

- Notice how frictional effects pulled the storm closer to Haiti than originally thought? It's almost as if the island was drawing the storm towards itself.

- Frictional effects can be a double-edged sword.. because once over Cuba, the opposite effect could take place in that once the northern 1/3 to 1/2 of the storm (not the center) crosses over land, the SE quadrant offshore winds will be the last to weaken, and the those winds funneling energy into the storm counter-clockwise could serve as a opposing force. What I mean by this is while I agree Ernesto will be fouled up by the highly mountainous terrain of eastern Cuba, I also think it is possible the storm will not linger over the island as long as is currently being projected. There are some theories (or perhaps it is a verifiable phenomenon of tropical systems) that storm centers can “sense” a source region of warm water and have a tendency to be drawn to the source if it is in close proximity to the center.

- Boy I guess the western flank of subtropical high weakened, like way way more than anyone anticipated. Here we were concerned this storm would be heading for New Orleans, or maybe Pensacola, and 500 miles later, there's speculation it may never actually hit the U.S. This trough that's moving into the northeast really has some cojones being that it's still . summer because it has completely changed the entire life cycle of this storm.

Since today is the first official day of school in Baltimore County and elsewhere I cannot post to the site during the day, but will issue an update via the distribution list this afternoon followed by a website update this evening,

Sunday, August 27, 2006

7:50 AM 8/27 - I discover this morning the forecast track has shifted significantly to the right, as other online forecasters had alluded to last week, and indeed they were right!

The culprit is (or will be) a digging shortwave low pressure system heading southeast from the Dakotas. The south- western flank of the subtropical High steering currents which serve as Ernesto's steering currents will react to this approaching change in the pressure gradient.

The net effect is a tightening of the isobars in advance of the storm, creating a pressure channel through which Ernesto will travel. In some cases the direction of the northern outflow channel of clouds can be an indication of the future path the storm will take in the near term of 24 hours.

Ernesto became a hurricane officially at 5:04 AM this morning, and if the above track hold true, Tampa-St. Petersburg could be looking at "the one" they've been fearing for years...a Category 3 monster with a 12 foot + storm surge that inundates the entire downtown and leaves St. Petersburg an island.

This scenario has been well-researched and published in Pinellas County papers. I'm sure this will soon be front page news Monday morning if it isn't already. As you can tell, the orientation of this projected path in relation to the coastline is what forecasters would consider the worse case scenario:

1. A strengthening major hurricane approaching a highly populated coast at an angle

2. A wide mouthed bay which will funnel surge waters far upstream, flooding small inlets already overwhelmed by 6-12 inches of rain that fell in advance of the storm.

3. A track that travels just north of the affected Bay area, giving it maximum exposure to the dangerous northeast quadrant, the portion of the storm with strongest winds & highest surge.

A built-in even worse situation could be that frictional effects due to land interaction of the NE quadrant cause onshore winds to weaken slightly.

Offshore winds end up being slightly stronger, and this drives the storm in a little sooner than expected.

That would result in Ernesto being forced up Tampa Bay. This is exactly the situation that occured with Charley in 2004.

Residents in Punta Gorda were under a hurricane warning, but saw that the projected path was going to take the storm more towards Tampa Bay, a considerable distance NORTH of Charlotte Harbor.

Saturday, August 26, 2006

Notice the big shift in track more towards North Central Gulf than what was shown in the 2pm advisory. This was a result of the circulation center reforming about 50 nautical miles toward the north-northeast...and more significantly, under the central dense overcast.

By now most of you who regularly monitor the tropics know that Ernesto is moving through the Caribbean and encountering moderate shear on his western flank. This has inhibited development despite the tropical cyclone being situated over favorable water temperatures. As the storm moves west ward through the central Caribbean this weekend, an upper level Low in the Yucatan-Caymans vicinity is likely to erode and retreat. This will enable an upper level high pressure ridge to become established over the system, which provides developing tropical cyclones the much needed “outflow/exhaust” mechanism. A ridge over the storm, in conjuction with very warm surface water (85 F+), and weakening shear all indicate Ernesto is likely to undergo a period of rapid strengthening leading up to and past Jamaica that may bring it to near Category 3 status by Tuesday or Wednesday.

If the storm moves into the southern and central Gulf as expected by Wednesday, it will be traveling along the western edge of the subtropical high pressure ridge extending from the Atlantic ocean. Concern over this dynamic is that the storm will slow down while also coming in contact with the “Loop current.” This is a notoriously warm but isolated gulf current that fueled Katrina, Rita and Wilma’s march to Category 5 last summer. It should be noted that Ernesto will enter the gulf at a time when it is climatologically the warmest of the year, and due to the less than active tropical season, even deep water currents have been able to warm significantly.

The combination of these factors means that Ernesto has the potential to make a US landfall anywhere along the Texas or Louisiana coast as a major hurricane in the Friday-Saturday time frame of next week. As of 5 PM Saturday, the most recent analysis of Ernesto's intensification and track shows we are starting to see a northward shift in the projected path, which now brings the Florida panhandle and possibly even the western coast of Florida at risk. If you are a resident of these areas or know anyone who is, I would strongly advise making advance preparations now to avoid the eventual supply and traffic rush that is to come. Consider that a hurricane watch would generally be issued when hurricane conditions are expected within 36-48 hours, which means a Friday afternoon landfall would be preceded by a Wednesday watch declaration. In terms of preparation time, residents who might be in the path of this storm currently have today, Sunday, Monday and Tuesday to begin preparing. Anyone waiting until Wednesday will face the frustration of long lines, limited supplies and extensive traffic. It is also a foregone conclusion that gas prices will increase PRIOR to and during the storm in anticipation of reduced production throughout the Gulf petroleum region.

Sunday, August 13, 2006

GO..ing into second half of August and still nothing to indicate that this season is headed for the record-books as was expected. My biggest concern is that the later we go in the season, I believe it's more likely that once a storm develops, it will be a BIG one. The system off Florida is in a less than favorable environment so not a threat for a while, but the Caribbean system has potential and thus will be watched closely. You can view the most updated satellite imagery, or check status of the latest recon flight.

Wednesday, August 9, 2006

Tropical enthusiasts have been following this one for a couple days now, and NOAA Reconnaissance aircraft recently investigated the storm to discover a pressure of 1010 mb with no closed center of circulation. Read NHC's latest report, and for sure we'll be watching this closely as it approaches the southern Caribbean. I will provide a detailed analysis if this system is named.

Thursday, August 3, 2006

The only relief for many of us in this inferno of a heat wave comes in the form of a fizzling little tropical system near Puerto Rico. Perhaps my dire predictions of an end-times future with a Category 5 Chris approaching the western Gulf states even scared him off. Yeah, that's probably what happened. It had nothing to do with a mid- and upper-level low that spun over the storm and snuffed off the anti-cyclonic outflow, effectively ending tropical cyclone characteristics. So with great pleasure I can announce that Chris will be a non-starter for the next few days until he can move into a more favorable environment and away from land, and there's a lot of land to get in his way between now and early next week.

For now, the tropics are (mostly) quiet and I hear that Dr. William Gray has lowered his final number of named storms for this season. I'm all about that. If Chris decides to rev up his engines again, I'll be back on it but for now I have a lot of paperwork to do and that is WAY more exciting, don't you think?

Wednesday, August 2, 2006

National Hurricane Center beginning to acknowledge in their discussions that official track guidance, denoted below by "OFCL" (last line on the key), is leaning towards a shift to the north and away from interaction with major landmasses such as Puerto Rico, Hispanola or Cuba. It appears the first piece of land Chris will affect in a major way, other than the Bahamas, is south Florida. If he does a Katrina and loop-de-loops somehow under Florida and through the straits, then we will be looking at Rita-redux. The combination of low shear, a strong high ridge dominating Eastern North America into the Atlantic, and warm SST's along with high heat potential in the central Gulf means we could be staring down the barrel of a Category 3 or greater by Tuesday or Wednesday, on it's way to a 5 before landfall along the western Gulf Coast.

Model guidance has shifted most projected paths north, avoiding the islands. Click on the image to view my source and other tropical cyclone model maps.

To look at this 5-day projection and not see the potential of a major hurricane by Monday, you'd have to be over in Egypt.... that is in "denial." The storm will be entering a very favorable environment late in the forecast period (from 96 to 120 hours), so that's why I expect to see NHC's official intensity increase to borderline Cat 3 for the Tuesday timeframe.

Those of you who remember Andrew in 1992 recall that it was a nondescript tropical storm, which was forecast initially to dissipate or remain weak as it approached Florida. Then, whamo! In just 30 hours, Andrew screamed up to Category 5 and remained a devastastingly strong storm all the way to the Florida coast. Chris certainly looks healthy enough with good outflow in all quadrants and a solid central dense overcast indicated by the consistent "orange ball" associated with strengthening systems. Click on the image above for a current loop.

I haven't pinpointed where the infamous "Loop current" is yet, but nevertheless with SSTs at 29 C and above from one end of the Gulf to another, this storm has plenty of time and energy to soak up before it makes landfall. I think this is going to be a rough ride for the Louisiana and Texas coasts, not to mention the Gulf oil rigs and gas refineries trying to get back on their feet from last year. Given the potential of this storm to interrupt the petroleum industry, I think I'll go fill up my 5 gallon gas cans today. Once this thing reaches hurricane strength and it goes on the radar screen of energy traders, you'll see a jump in gas prices over the next week, especially when you consider the triple whammy of oil companies having to shut down operations early to remove personnel, then tankers being diverted to other ports, and lastly the current 12% of shut in production left over from last year.11:30 addendum..in midday trading, oil was topping $76 a barrel, too late... traders already see the danger ahead.

A map of offshore mobile and onshore fixed oil rigs in the Gulf of Mexico, from riglogix.com. It'd be a cryin' shame if Chris sliced through the area that was not as affected by either of last year's megastorms.

Tuesday, August 1, 2006

Foot's Forecast is officially back on line after the longest hiatus since... well, ever. No I didn't catch the bird flu or head to my bug out station. I just didn't want to expend valuable brainpower on wimpy little storms, and had to finish our new deck in the backyard before the season got going. So in that sense Chris's timing is good, but as Han Solo would say, "I have a bad feeling about this." My kickoff statement on this storm is that Chris will be unpredictable, confound the experts, and full of surprises right to the very end. He already has thrown a monkey wrench into the NHC official forecast twice in the past 24 hours, and I suspect that is only the beginning. My meteorological gut tells me this has Southern Florida and the Western Gulf written all over it, and I'll explain why soon. Based on the intensification trend thus far, we might be looking at a hurricane by Wednesday evening.

The short list on Chris is:1. Will be a hurricane in 24 hours2. Will not dissipate as NHC and models originally projected, due to presence of large Bermuda high and other upper-level factors skewing model initialization of the storm.3. Will probably enter Gulf by hook or crook as borderline major hurricane (or if crossing Florida, baseline Cat 1)4. A turn up the SE coast unlikely due to overpowering influence of the heat wave death grip high pressure ridge5. A landfall along the Gulf Coast as a major hurricane looks likely if the storm limits interaction with land and is able to squeeze through the Florida straits just like our friends from last year, Katrina and Rita.

Who's at most risk?Based on the analysis above, I would put the landfall zone from west of the Mississippi Delta over to Corpus Christi, Texas. Arrival time: sometime next Wednesday or Thursday.